US4058732A - Method and apparatus for improved analytical fluorescent spectroscopy - Google Patents

Method and apparatus for improved analytical fluorescent spectroscopy Download PDF

Info

Publication number
US4058732A
US4058732A US05/591,305 US59130575A US4058732A US 4058732 A US4058732 A US 4058732A US 59130575 A US59130575 A US 59130575A US 4058732 A US4058732 A US 4058732A
Authority
US
United States
Prior art keywords
fluorescent
target substance
fluorescence
pulse
substances
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/591,305
Inventor
Irwin Wieder
Original Assignee
Analytical Radiation Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Analytical Radiation Corp filed Critical Analytical Radiation Corp
Priority to US05/591,305 priority Critical patent/US4058732A/en
Priority claimed from US05/635,411 external-priority patent/US4341957A/en
Priority to DE2660391A priority patent/DE2660391C2/en
Priority to DE2628158A priority patent/DE2628158C3/en
Priority to IT24821/76A priority patent/IT1062498B/en
Priority to FR7619720A priority patent/FR2316595A1/en
Priority to GB27047/76A priority patent/GB1560402A/en
Priority to GB2827/79A priority patent/GB1560403A/en
Priority to CA255,924A priority patent/CA1082106A/en
Priority to JP51077667A priority patent/JPS5210796A/en
Publication of US4058732A publication Critical patent/US4058732A/en
Application granted granted Critical
Assigned to WIEDER, IRWIN reassignment WIEDER, IRWIN ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: ANALYTICAL RADIATION CORPORATION
Priority to JP18498885A priority patent/JPS61153568A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/64—Fluorescence; Phosphorescence
    • G01N21/6408—Fluorescence; Phosphorescence with measurement of decay time, time resolved fluorescence
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/64—Fluorescence; Phosphorescence
    • G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
    • G01N33/531—Production of immunochemical test materials
    • G01N33/532—Production of labelled immunochemicals
    • G01N33/533—Production of labelled immunochemicals with fluorescent label
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S436/00—Chemistry: analytical and immunological testing
    • Y10S436/80—Fluorescent dyes, e.g. rhodamine

Definitions

  • the invention relates to spectrofluorometers, and more particularly to an improved spectrofluorometric method and apparatus which minimizes the effect of background or competing fluorescence.
  • a sample containing a material of unknown quantity, i.e. target molecules is placed in a holder.
  • the sample may be in the form of a liquid solution or a solid on a substrate such as filter paper.
  • the sample is then exposed to radiation of known spectral distribution, characteristically a restricted bandwidth of light.
  • the distribution of excitation radiation is within the excitation spectrum of target molecules and preferably near the maximum.
  • the emission spectrum following irradiation is at longer wavelengths and is characteristic of the target molecules. Its intensity is measured to indicate the quantity of target molecules.
  • spectrofluorometers One problem with present spectrofluorometers is that their sensitivity is limited due to noise in the excitation and detection systems and secondly, due to competing fluorescence from ambient substances, such as from substrate materials, sample containers, particles in the air, other fluorescing species in the sample, reagents and the like.
  • Another object is to devise an improved spectrofluorometer for detecting very small quantities of target molecules in the presence of competing background fluorescence.
  • I have devised a new method for fluorescent spectroscopy of target substances which includes the steps of first isolating molecules of target substances and then tagging target molecules with a fluorescent tag having a relatively long fluorescent decay lifetime compared with the decay lifetime of ambient substances. These ambient substances may have emission spectra in the same wavelength range as target molecules.
  • the tagged target molecules are excited with intense pulses of radiation having the appropriate spectral distribution, i.e. within the excitation spectrum of target molecules and preferably near the maximum, each pulse having a pulse duration which is short compared with the relatively long fluorescent decay lifetime of the fluorescent tag.
  • a fluorescence detection system is gated on only after the fluorescence of ambient substances, which cause the deleterious competing fluorescence, has substantially decayed.
  • a new fluorescent spectrofluorometer is utilized, providing an intense pulsed excitation source for target molecules by means of a pulsed excitation source, such as a pulsed dye laser excited by a nitrogen laser or by a nitrogen laser alone.
  • a fluorescent detection system i.e. a detection means, typically utilizing a photomultiplier, is spaced apart from the excitation source and positioned to receive fluorescent radiation emission from target molecules and ambient substances in response to excitation pulses.
  • An electronic gate turns the detection system on only after competing fluorescence has decayed.
  • competing fluorescence has substantially decayed at the time the detection system is gated on, so that the detection system can measure the emission spectra of the target molecules only.
  • FIG. 1 is a plan view of the apparatus of the present invention.
  • FIG. 2a is an intensity plot versus time of a laser excitation pulse.
  • FIG. 2b is an intensity plot versus time of fluorescent emission of ambient substances.
  • FIG. 2c is an intensity plot versus time of the emission of tagged target molecules in accord with the method of the present invention.
  • target substances the quantity of which is to be determined
  • a fluorescent tag which has a relatively long fluorescent decay lifetime, compared with decay lifetimes of ambient substances.
  • the target material has been previously separated from other substances by known techniques, such as by chromatography or by antibody fixation.
  • An example of separation by antibody fixation is as follows. A quantity of antibody specific to a target material is deposited on a solid matrix, such as cellulose acetate. An unknown quantity of target molecules in solution and specific to the selected antibodies is exposed to the matrix and reacts with the selected antibodies thus becoming fixed to the substrate. See the article entitled, "The Fluorescent Antibody Technique Applied to Titration and Identification of Antigens in Solutions or Antisera” in Proc. Soc. Experimental Biology, Vol. 113, p. 394-397 by F. Paronetto (1963), which is incorporated by reference herein.
  • a fluorotag i.e. a fluorescent tagging material having an affinity for the target material, is used to tag the target and the excess tag is washed away.
  • Each fluorotag is selected to have a period of fluorescence long compared to competing background fluorescence. For example, a fluorotag whose decay lifetime is at least ten times the duration of competing background fluorescence would be desirable. Either of the exemplary fluorotags discussed below may be used with each of the separation methods.
  • a first exemplary class of fluorotags consists of rare earth-organo complexes. These consist of a rare earth bound to an organic compound with the resulting complex having desired properties. These properties are efficient excitation at convenient wavelengths, good excitation transfer to the rare earth, high quantum efficiency at ordinary temperatures, narrow emission spectrum, and very long lifetimes. It is believed that the complex transfers its excitation to the rare earth and it is the intensity of the emission spectra of the rare earth which is measured and correlated with the amount of rare earth-organo complex present. If rare earth-organo complex molecules have been bound to a target molecule in a fixed ratio, the amount of target material can be inferred in accord with the method and apparatus disclosed herein.
  • Rare earth-organo complexes which have been found to have the above desired properties are europium benzoylacetonate and europium benzoyltrifluoroacetonate.
  • the fluorescence of the former compound and other similar compounds is discussed by S. I. Weissman in the Journal of Chemical Physics, Vol. 10, p. 214-217, 1942, incorporated by reference herein.
  • pyrenebuterate Another class of fluorotags which have relatively long decay lifetimes, over 100 n.s., is represented by pyrenebuterate. Preparation of pyrenebuterate and typical fluorescent lifetimes are discussed by Knopp and Weber in the Journal of Biological Chemistry, Vol. 242, p. 1353 (1967) and Vol. 244, p. 6309 (1969), incorporated by reference herein.
  • the fluorotags may be attached to target molecules, depending on the target, in two ways: by ordinary chemical combination (non-specific), or by biological chemical action (specific). In the latter case, fluorescent antibodies, specific to the target antigens, are selected for capture by the antigens in a known ratio and the excess fluorotag is washed away. The procedure for tagging antigens with fluorescent antibodies is described in Fluorescent Antibody Techniques and Their Applications, A. Kawamura, Ed., University Park Press, Baltimore, MD., 1969, incorporated by reference herein.
  • the target molecules have been isolated on a substrate, tagged and supported, as by support 21.
  • the tagged target substance is excited by excitation source 23, having a known output spectrum.
  • the output is in the form of a beam 25 which is substantially monochromatic, and in the present embodiment, pulsed radiation, typically from a laser is employed.
  • the pulse duration is at least ten times shorter than fluorotag fluorescence lifetime.
  • a tunable dye laser excited by a pulsed nitrogen laser exciter 27 causes a very strong excitation.
  • a pulsed nitrogen laser alone operating at 3371A causes very strong excitation. Either laser is preferred because high peak power and relatively short duration pulses can be obtained, at a wavelength within the excitation spectrum of most substances.
  • the filtered and focused output from a simple pulsed gas discharge can also be used, provided its duration is at least ten times shorter than the fluorescent lifetime of the fluorotag.
  • Beam 25 is directed toward target molecules on support 21.
  • the target molecules may alternatively be in solution in a vial.
  • Emission from substrate 21 is indicated by the dashed lines 31 which are collected by a lens 33 and passed through a filter, such as an interference filter 35 and thence to a detector 37, which is typically a photomultiplier tube.
  • Interference filter 35 has a wavelength bandpass centered at the emission wavelength of the emission radiation of the fluorescent tagging material and filters out excitation wavelength radiation from source 23 scattered toward detector 37.
  • Detection 37 which is "on" at all times produces an electrical signal proportional to the fluorescent radiation emission received and which is amplified by a linear amplifier 38 which then passes the amplified signals to a gating circuit 39.
  • the gating circuit is opened (on) and closed (off) by two signals from delay circuit 36. These two signals are generated at two fixed times after the excitation pulse is sensed by phototube 34. The resulting signal from phototube 34 starts a timing sequence in circuit 36 which then generates the delayed signals.
  • the amount of delay selected in the delay circuit 36 for the first signal is preferably selected to be at least 5 background fluorescent lifetimes. For example, if the lifetime of background or ambient fluorescence is 10 nanoseconds, the selected first delay is preferably 50 nanoseconds. If the decay of ambient fluorescence is by an exponential decay mode, 5 decay lifetimes represent a reduction in the background or ambient fluorescence to about 0.7% of its peak value.
  • Gating circuit 39 is kept open until the second delayed signal from delay circuit 36 arrives. This should be at a time preferably 2 decay lifetimes of the fluorescent tag, for example, approximately 200 nanoseconds for pyrenebutyrate.
  • the linearly amplified signal from amplifier 38 passes into the signal processor 43 which averages the results of many pulses and which correlates the amplified signal with information characterizing the emission of known quantities of the target material.
  • the output of signal processor 43 is thereby indicative of the quantity of target molecules.
  • the pulse amplitude of an excitation pulse is shown by the ordinate axis and time is shown as the abscissa.
  • the duration of the pulse (time between its half-intensity points) is indicated by the arrow and is shown to be 3 nanoseconds.
  • lifetime is defined as the time at which the fluorescent intensity has decayed to 1/e of its initial value where e is the base of the natural system of logarithms.
  • FIG. 2b illustrates ambient fluorescence relative to an excitation pulse with the same zero starting time as in FIG. 2a.
  • the intensity of ambient fluorescent is shown as the ordinate and time as the abscissa in plot.
  • the lifetime of ambient fluorescence, i.e. combined from all sources, including particles in the air, reagants, holder materials, other fluorescing species in the sample and the like is shown to be approximately 10 nanoseconds and decays toward zero.
  • FIG. 2c the intensity of a typical fluorescent tag material is plotted, with the intensity shown as the ordinate and time shown as the abscissa.
  • the lifetime is shown to be 100 nanoseconds, as indicated by the arrow in FIG. 2c.
  • FIG. 2c shares a common zero time with FIGS. 2a and 2b and the time gating circuit is held off is indicated to the left of the left hand dashed line in FIG. 2c. After that time has elapsed, the gate is open or on and the gate is maintained on for 2 lifetimes of the fluorescent tag or approximately 200 nanoseconds for pyrenebutyrate.
  • the total time in which the gating circuit 39 of FIG. 1 is kept on is indicated in FIG. 2c as the time between the two dashed lines, or from 50 to 200 nanoseconds after time zero. The process is then repeated.
  • the improved method of the present invention is carried out by tagging target materials with a fluorescent tag having a relatively long decay lifetime compared with competing ambient substances.
  • Two exemplary tagging materials are rare earth-organo complexes of the type which have very long decay lifetimes, nearly 10 -3 seconds, and pyrenebuterate, which has a lifetime in excess of 100 nanoseconds.
  • tagging materials While certain exemplary tagging materials have been described herein, other tagging materials may be known to those skilled in the art and the examples given herein are not intended to be restrictive.
  • the method disclosed herein contemplates use of a fluorescent tag which has a long decay lifetime compared to the fluorescent decay lifetime of ambient substances. However, some preference has been given in the preferred embodiment to those fluorescent tags which also have sharp emission spectra which assist in discriminating against unwanted fluorescence.

Abstract

A method is disclosed whereby the molecules of a chemical substance to be measured, referred to as target molecules, are combined with fluorescent molecules having a relatively long fluorescent decay lifetime. These tagged target molecules are excited with an intense pulse of ultraviolet or visible radiation, and a detection system is gated on only after background fluorescence has substantially decayed, but while the fluorescent tag attached to the target molecules is still actively decaying. The amount of fluorescent tag emission which is measured is indicative of the target molecule content of the sample. An apparatus for improved fluorescent spectrofluorometry includes a pulsed excitation source and a gating means connected to a detection system for gating the detection system on after tagged target molecules have been excited and competing background fluorescence has substantially decayed, but before tagged target molecules have substantially decayed.

Description

BACKGROUND OF THE INVENTION
a. Field of the Invention
The invention relates to spectrofluorometers, and more particularly to an improved spectrofluorometric method and apparatus which minimizes the effect of background or competing fluorescence.
B. Prior Art
In fluorescent spectroscopy, a sample containing a material of unknown quantity, i.e. target molecules, is placed in a holder. The sample may be in the form of a liquid solution or a solid on a substrate such as filter paper. The sample is then exposed to radiation of known spectral distribution, characteristically a restricted bandwidth of light. The distribution of excitation radiation is within the excitation spectrum of target molecules and preferably near the maximum. The emission spectrum following irradiation is at longer wavelengths and is characteristic of the target molecules. Its intensity is measured to indicate the quantity of target molecules.
One problem with present spectrofluorometers is that their sensitivity is limited due to noise in the excitation and detection systems and secondly, due to competing fluorescence from ambient substances, such as from substrate materials, sample containers, particles in the air, other fluorescing species in the sample, reagents and the like.
Prior to the filing of this patent application, a pulsed dye laser has been reported for use in a spectrofluorometer. See the article entitled "New Type of Spectrofluorometer with a Tunable Laser Source and Unique Optical System" by D. C. Harrington and H. V. Malmstadt, Analytical Chemistry, Vol. 47, No. 2, February 1975, p. 271-276.
Use of a pulsed laser to stimulate fluorescent emission from target molecules improves the signal to noise ratio to a certain extent. However, while the signal to noise ratio is enhanced, the problem of competing fluorescence is still present. When the amount of target material is very small, perhaps a few parts per billion or less, the fluorescence of the target molecules may not be detected because it may be weaker than the combined fluorescence from all background sources.
It is therefore an object of the invention to provide a method for detecting very small quantities of target molecules in the presence of competing background fluorescence.
Another object is to devise an improved spectrofluorometer for detecting very small quantities of target molecules in the presence of competing background fluorescence.
SUMMARY OF THE INVENTION
I have devised a new method for fluorescent spectroscopy of target substances which includes the steps of first isolating molecules of target substances and then tagging target molecules with a fluorescent tag having a relatively long fluorescent decay lifetime compared with the decay lifetime of ambient substances. These ambient substances may have emission spectra in the same wavelength range as target molecules. Next, the tagged target molecules are excited with intense pulses of radiation having the appropriate spectral distribution, i.e. within the excitation spectrum of target molecules and preferably near the maximum, each pulse having a pulse duration which is short compared with the relatively long fluorescent decay lifetime of the fluorescent tag. Then, a fluorescence detection system is gated on only after the fluorescence of ambient substances, which cause the deleterious competing fluorescence, has substantially decayed.
A new fluorescent spectrofluorometer is utilized, providing an intense pulsed excitation source for target molecules by means of a pulsed excitation source, such as a pulsed dye laser excited by a nitrogen laser or by a nitrogen laser alone. A fluorescent detection system, i.e. a detection means, typically utilizing a photomultiplier, is spaced apart from the excitation source and positioned to receive fluorescent radiation emission from target molecules and ambient substances in response to excitation pulses. An electronic gate turns the detection system on only after competing fluorescence has decayed.
Utilizing the method and apparatus disclosed herein, competing fluorescence has substantially decayed at the time the detection system is gated on, so that the detection system can measure the emission spectra of the target molecules only.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of the apparatus of the present invention.
FIG. 2a is an intensity plot versus time of a laser excitation pulse.
FIG. 2b is an intensity plot versus time of fluorescent emission of ambient substances.
FIG. 2c is an intensity plot versus time of the emission of tagged target molecules in accord with the method of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the method of the present invention, it is necessary to tag target substances, the quantity of which is to be determined, with a fluorescent tag which has a relatively long fluorescent decay lifetime, compared with decay lifetimes of ambient substances. The target material has been previously separated from other substances by known techniques, such as by chromatography or by antibody fixation.
An example of separation by antibody fixation is as follows. A quantity of antibody specific to a target material is deposited on a solid matrix, such as cellulose acetate. An unknown quantity of target molecules in solution and specific to the selected antibodies is exposed to the matrix and reacts with the selected antibodies thus becoming fixed to the substrate. See the article entitled, "The Fluorescent Antibody Technique Applied to Titration and Identification of Antigens in Solutions or Antisera" in Proc. Soc. Experimental Biology, Vol. 113, p. 394-397 by F. Paronetto (1963), which is incorporated by reference herein.
Once a separation of the target material is achieved a fluorotag, i.e. a fluorescent tagging material having an affinity for the target material, is used to tag the target and the excess tag is washed away.
At least two types of fluorescent tags may be utilized. Each fluorotag is selected to have a period of fluorescence long compared to competing background fluorescence. For example, a fluorotag whose decay lifetime is at least ten times the duration of competing background fluorescence would be desirable. Either of the exemplary fluorotags discussed below may be used with each of the separation methods.
A first exemplary class of fluorotags consists of rare earth-organo complexes. These consist of a rare earth bound to an organic compound with the resulting complex having desired properties. These properties are efficient excitation at convenient wavelengths, good excitation transfer to the rare earth, high quantum efficiency at ordinary temperatures, narrow emission spectrum, and very long lifetimes. It is believed that the complex transfers its excitation to the rare earth and it is the intensity of the emission spectra of the rare earth which is measured and correlated with the amount of rare earth-organo complex present. If rare earth-organo complex molecules have been bound to a target molecule in a fixed ratio, the amount of target material can be inferred in accord with the method and apparatus disclosed herein.
Representative rare earth-organo complexes which have been found to have the above desired properties are europium benzoylacetonate and europium benzoyltrifluoroacetonate. The fluorescence of the former compound and other similar compounds is discussed by S. I. Weissman in the Journal of Chemical Physics, Vol. 10, p. 214-217, 1942, incorporated by reference herein.
Another class of fluorotags which have relatively long decay lifetimes, over 100 n.s., is represented by pyrenebuterate. Preparation of pyrenebuterate and typical fluorescent lifetimes are discussed by Knopp and Weber in the Journal of Biological Chemistry, Vol. 242, p. 1353 (1967) and Vol. 244, p. 6309 (1969), incorporated by reference herein.
The fluorotags may be attached to target molecules, depending on the target, in two ways: by ordinary chemical combination (non-specific), or by biological chemical action (specific). In the latter case, fluorescent antibodies, specific to the target antigens, are selected for capture by the antigens in a known ratio and the excess fluorotag is washed away. The procedure for tagging antigens with fluorescent antibodies is described in Fluorescent Antibody Techniques and Their Applications, A. Kawamura, Ed., University Park Press, Baltimore, MD., 1969, incorporated by reference herein.
The preparation of an antibody conjugate with pyrenebutyrate, i.e. a fluorescent antibody, is described in the article "The Rotational Diffusion of Thyroglobulin" in the Journal of Biological Chemistry, Vol. 244, No. 23, 1969, p. 6543-6547 by A. W. Rawitch et al., incorporated by reference herein.
Referring now to FIG. 1, the target molecules have been isolated on a substrate, tagged and supported, as by support 21. The tagged target substance is excited by excitation source 23, having a known output spectrum. Usually the output is in the form of a beam 25 which is substantially monochromatic, and in the present embodiment, pulsed radiation, typically from a laser is employed. The pulse duration is at least ten times shorter than fluorotag fluorescence lifetime. We have found that a tunable dye laser excited by a pulsed nitrogen laser exciter 27 causes a very strong excitation. Alternatively a pulsed nitrogen laser alone operating at 3371A causes very strong excitation. Either laser is preferred because high peak power and relatively short duration pulses can be obtained, at a wavelength within the excitation spectrum of most substances.
Alternatively, the filtered and focused output from a simple pulsed gas discharge can also be used, provided its duration is at least ten times shorter than the fluorescent lifetime of the fluorotag.
Beam 25 is directed toward target molecules on support 21. The target molecules may alternatively be in solution in a vial.
Emission from substrate 21 is indicated by the dashed lines 31 which are collected by a lens 33 and passed through a filter, such as an interference filter 35 and thence to a detector 37, which is typically a photomultiplier tube. Interference filter 35 has a wavelength bandpass centered at the emission wavelength of the emission radiation of the fluorescent tagging material and filters out excitation wavelength radiation from source 23 scattered toward detector 37.
Detection 37 which is "on" at all times produces an electrical signal proportional to the fluorescent radiation emission received and which is amplified by a linear amplifier 38 which then passes the amplified signals to a gating circuit 39. The gating circuit is opened (on) and closed (off) by two signals from delay circuit 36. These two signals are generated at two fixed times after the excitation pulse is sensed by phototube 34. The resulting signal from phototube 34 starts a timing sequence in circuit 36 which then generates the delayed signals.
The amount of delay selected in the delay circuit 36 for the first signal is preferably selected to be at least 5 background fluorescent lifetimes. For example, if the lifetime of background or ambient fluorescence is 10 nanoseconds, the selected first delay is preferably 50 nanoseconds. If the decay of ambient fluorescence is by an exponential decay mode, 5 decay lifetimes represent a reduction in the background or ambient fluorescence to about 0.7% of its peak value.
Gating circuit 39 is kept open until the second delayed signal from delay circuit 36 arrives. This should be at a time preferably 2 decay lifetimes of the fluorescent tag, for example, approximately 200 nanoseconds for pyrenebutyrate.
After signal gating by the gating circuit 39 which acts as a switch, the linearly amplified signal from amplifier 38 passes into the signal processor 43 which averages the results of many pulses and which correlates the amplified signal with information characterizing the emission of known quantities of the target material. The output of signal processor 43 is thereby indicative of the quantity of target molecules.
In FIG. 2a, the pulse amplitude of an excitation pulse is shown by the ordinate axis and time is shown as the abscissa. The duration of the pulse (time between its half-intensity points) is indicated by the arrow and is shown to be 3 nanoseconds. When fluorescent lifetime (not duration) is discussed herein, lifetime is defined as the time at which the fluorescent intensity has decayed to 1/e of its initial value where e is the base of the natural system of logarithms.
FIG. 2b illustrates ambient fluorescence relative to an excitation pulse with the same zero starting time as in FIG. 2a. The intensity of ambient fluorescent is shown as the ordinate and time as the abscissa in plot. The lifetime of ambient fluorescence, i.e. combined from all sources, including particles in the air, reagants, holder materials, other fluorescing species in the sample and the like is shown to be approximately 10 nanoseconds and decays toward zero.
In FIG. 2c, the intensity of a typical fluorescent tag material is plotted, with the intensity shown as the ordinate and time shown as the abscissa. The lifetime is shown to be 100 nanoseconds, as indicated by the arrow in FIG. 2c. FIG. 2c shares a common zero time with FIGS. 2a and 2b and the time gating circuit is held off is indicated to the left of the left hand dashed line in FIG. 2c. After that time has elapsed, the gate is open or on and the gate is maintained on for 2 lifetimes of the fluorescent tag or approximately 200 nanoseconds for pyrenebutyrate. Thus, the total time in which the gating circuit 39 of FIG. 1 is kept on is indicated in FIG. 2c as the time between the two dashed lines, or from 50 to 200 nanoseconds after time zero. The process is then repeated.
In summary, the improved method of the present invention is carried out by tagging target materials with a fluorescent tag having a relatively long decay lifetime compared with competing ambient substances. Two exemplary tagging materials are rare earth-organo complexes of the type which have very long decay lifetimes, nearly 10-3 seconds, and pyrenebuterate, which has a lifetime in excess of 100 nanoseconds.
By keeping a fluorescence detection system gated off during most of the decay of ambient fluorescence, and then gating the detection system on to observe fluorescence of the tagging material, advantage is taken of the relatively long fluorescent lifetime of the tagging material. Further signal enhancement is obtained when the tagging material has very sharp emission spectra, as do rare earth complexes, by utilizing an interference filter to discriminate against unwanted wavelengths which fall outside the sharp emission passband of the interference filter.
While certain exemplary tagging materials have been described herein, other tagging materials may be known to those skilled in the art and the examples given herein are not intended to be restrictive. The method disclosed herein contemplates use of a fluorescent tag which has a long decay lifetime compared to the fluorescent decay lifetime of ambient substances. However, some preference has been given in the preferred embodiment to those fluorescent tags which also have sharp emission spectra which assist in discriminating against unwanted fluorescence.

Claims (25)

I claim:
1. A method for fluorescent spectroscopy of a target substance comprising:
isolating a target substance,
tagging said target substance with a fluorescent tag having a long fluorescent decay lifetime compared to the longest of the decay lifetimes of competing untagged ambient substances,
removing excess fluorescent tag,
exciting the tagged target substance with at least one pulse of radiation, said pulse having a pulse duration which is short compared to the fluorescent decay lifetime of said fluorescent tag,
detecting the fluorescence of said excited tagged target substances after the fluorescence of said ambient substances has substantially decayed.
2. The method of claim 1 whereby isolating said target substance is by means of chromatography.
3. The method of claim 1 whereby isolating said target substance is by means of combination with antibodies fixed on a substrate.
4. The method of claim 1 wherein said fluorescent tag is a fluorescent antibody specific to the target substance.
5. The method of claim 4 wherein said fluorescent antibody is an antibody conjugated with pyrenebutyrate.
6. The method of claim 1 wherein said fluorescent tag is a fluorescent rare earth-organo complex.
7. The method of claim 6 wherein said fluorescent rare earth-organo complex is europium benzoyltrifluoroacetonate.
8. The method of claim 1 wherein said fluorescent tag is pyrenebutyrate.
9. The method of claim 1 wherein said fluorescent detection system is gated on after five lifetimes of background fluorescence from the target.
10. The method of claim 1 wherein said exciting pulse is derived from a laser source.
11. The method of claim 10 wherein said exciting pulse is derived from a nitrogen laser source.
12. The method of claim 1 wherein said exciting pulse is derived from a pulsed dye laser excited by a nitrogen laser.
13. In a method of fluorescent spectroscopy for a target substance wherein at least one pulse of excitation radiation of relatively short duration is directed toward the target substance the improvement comprising, combining with said target substance a fluorescent tag specific to the target substance with fluorescent decay lifetime long compared with the longest of the fluorescent decay lifetimes of competing untagged ambient substances and detecting said tagged target substance after fluorescence of competing ambient substances substantially decayed.
14. The method of claim 13 wherein said fluorescent tag is a fluorescent rare earth-organo complex.
15. The method of claim 13 wherein said fluorescent tag is a fluorescent antibody specific to said target substance.
16. The method of claim 15 wherein the fluorescent antibody is an antibody conjugated with pyrenebutyrate.
17. A method for fluorescent spectroscopy of a target substance amid ambient substances comprising;
tagging a target substance with a fluorescent tag specific to the target substance having a long fluorescent decay lifetime compared to the longest of the decay lifetimes of competing untagged ambient substances,
removing excess fluorescent tag,
exciting the tagged target substance for fluorescence with at least one pulse of radiation, said pulse having a pulse duration which is short compared to the fluorescent decay lifetime of said fluorescent tag,
detecting the fluorescence of said excited tagged target substances after the fluorescence of said ambient substances has substantially decayed.
18. The method of claim 17 wherein said fluorescent tag is a fluorescent antibody specific to the target substance.
19. A fluorometer system for fluorescent spectroscopy of target substances comprising,
an amount of target substance amid untagged ambient substances, said target substance tagged with a fluorescent tag having a long fluorescent decay lifetime compared to the longest of the decay lifetimes of competing ambient substances,
radiation means having an output directed at said target substance for exciting said tagged target substance into fluorescence with at least one pulse of radiation, said pulse having a pulse duration which is short compared to the long fluorescent decay lifetime of said fluorescent tag,
a fluorescence detector, disposed for receiving fluorescence from said tagged target substance, having means for detecting said fluorescence after the fluorescence of competing ambient substances has substantially decayed and having gating means connected to said detecting means for gating on said fluorescence detector after said fluorescence of competing ambient substances has substantially decayed, and
means for correlating the detected fluorescence of the tagged target substance with the amount of tagged target substance
20. The apparatus of claim 19 wherein said target is supported on a solid matrix.
21. The apparatus of claim 19 wherein said radiation means is a pulsed dye laser.
22. The apparatus of claim 19 wherein said radiation means is a pulsed nitrogen laser.
23. The apparatus of claim 19 wherein said radiation means is a pulsed dye laser excited by a nitrogen laser.
24. The apparatus of claim 19 wherein said radiation means is a pulsed gas discharge.
25. The apparatus of claim 19 wherein said gating means is connected to a delay circuit means for establishing a selected time for fluorescent radiation from said ambient substances to substantially decay.
US05/591,305 1975-06-30 1975-06-30 Method and apparatus for improved analytical fluorescent spectroscopy Expired - Lifetime US4058732A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
US05/591,305 US4058732A (en) 1975-06-30 1975-06-30 Method and apparatus for improved analytical fluorescent spectroscopy
DE2660391A DE2660391C2 (en) 1975-06-30 1976-06-23 Fluorescent antibody
DE2628158A DE2628158C3 (en) 1975-06-30 1976-06-23 Method for fluorescence spectroscopy of a target substance
IT24821/76A IT1062498B (en) 1975-06-30 1976-06-28 APPARATUS METHOD AND COMPOSITIONS FOR FLUORESCENCE SPECTROSCOPY AND IMMUNOFLUORIMETRIC ANALYSIS
GB2827/79A GB1560403A (en) 1975-06-30 1976-06-29 Fluorescent antibodies
GB27047/76A GB1560402A (en) 1975-06-30 1976-06-29 Analytical fluorescent spectroscopy and immundofluorometric assay
FR7619720A FR2316595A1 (en) 1975-06-30 1976-06-29 METHOD, APPARATUS AND PRODUCTS FOR ANALYTICAL FLUORESCENT SPECTROMETRY AND IMMUNOFLUOROMETRIC ASSAY
CA255,924A CA1082106A (en) 1975-06-30 1976-06-29 Method, apparatus, and compositions for analytical fluorescent spectroscopy and immunofluorometric assay
JP51077667A JPS5210796A (en) 1975-06-30 1976-06-30 Keikobunseki hoho oyobi sochi
JP18498885A JPS61153568A (en) 1975-06-30 1985-08-21 Fluorescent antibody for immunofluorescent analysis

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US05/591,305 US4058732A (en) 1975-06-30 1975-06-30 Method and apparatus for improved analytical fluorescent spectroscopy
US05/635,411 US4341957A (en) 1975-11-26 1975-11-26 Fluorescent antibody composition for immunofluorometric assay

Publications (1)

Publication Number Publication Date
US4058732A true US4058732A (en) 1977-11-15

Family

ID=27081110

Family Applications (1)

Application Number Title Priority Date Filing Date
US05/591,305 Expired - Lifetime US4058732A (en) 1975-06-30 1975-06-30 Method and apparatus for improved analytical fluorescent spectroscopy

Country Status (7)

Country Link
US (1) US4058732A (en)
JP (1) JPS5210796A (en)
CA (1) CA1082106A (en)
DE (2) DE2628158C3 (en)
FR (1) FR2316595A1 (en)
GB (2) GB1560402A (en)
IT (1) IT1062498B (en)

Cited By (96)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4150295A (en) * 1978-01-05 1979-04-17 Analytical Radiation Corporation Method and apparatus for background correction in photoluminescent analysis
US4171956A (en) * 1977-06-13 1979-10-23 General Electric Company Laser immunoassay
US4198567A (en) * 1977-10-25 1980-04-15 Peter Eneroth Method and apparatus for discrimination between scattered excitation radiation and low level fast decaying fluorescent radiation
US4222744A (en) * 1978-09-27 1980-09-16 Becton Dickinson & Company Assay for ligands
US4238195A (en) * 1979-01-18 1980-12-09 Miles Laboratories, Inc. Fluorescer-labeled specific binding assays
US4259574A (en) * 1979-11-06 1981-03-31 International Business Machines Corporation Microanalysis by pulse laser emission spectroscopy
US4284897A (en) * 1977-04-30 1981-08-18 Olympus Optical Company Ltd. Fluorescence determining microscope utilizing laser light
US4341957A (en) * 1975-11-26 1982-07-27 Analytical Radiation Corporation Fluorescent antibody composition for immunofluorometric assay
EP0064484A2 (en) * 1981-04-30 1982-11-10 Wallac Oy Method for fluorescence spectroscopic determination of a biologically active substance
US4373932A (en) * 1980-01-11 1983-02-15 Akzona Incorporated Application of water-dispersible hydrophobic dyes or pigments as labels in immunoassays
US4374120A (en) * 1979-03-08 1983-02-15 Wallac Oy Fluorescence spectroscopy assay means with fluorescent chelate of a lanthanide
US4390274A (en) * 1979-01-18 1983-06-28 Fritz Berthold Use of a method, particularly an automatic method, for measuring light as well as improvements and apparatuses for carrying out the same
US4432907A (en) * 1979-09-10 1984-02-21 Analytical Radiation Corporation Diamine acid fluorescent chelates
US4614723A (en) * 1983-06-03 1986-09-30 Hoffmann-La Roche Inc. Porphyrin derivatives as fluorescent markers for immunoassays
US4637988A (en) * 1981-07-01 1987-01-20 Eastman Kodak Company Fluorescent labels for immunoassay
WO1987004716A1 (en) * 1986-01-30 1987-08-13 Salifu Dakubu Use of lanthanide chelate fluorophores based on dihydropyridine condensation products
EP0242527A2 (en) * 1986-02-19 1987-10-28 Enzo Biochem, Inc. Analyte detection by means of energy transfer
WO1987007955A1 (en) * 1986-06-17 1987-12-30 Baxter Travenol Laboratories, Inc. Homogeneous fluoroassay methods employing fluorescent background rejection and water-soluble rare earth metal chelate fluorophores
US4778593A (en) * 1983-03-25 1988-10-18 Agency Of Industrial Science And Technology Method and apparatus for discriminating minute particles
US4791310A (en) * 1986-10-02 1988-12-13 Syracuse University Fluorescence microscopy
US4794191A (en) * 1981-07-01 1988-12-27 Eastman Kodak Company Fluorescent chelates
US4801722A (en) * 1981-07-01 1989-01-31 Eastman Kodak Company Coumarin chelates
US4808541A (en) * 1983-03-15 1989-02-28 Lkb Produkter Ab Determination method utilizing reagents covalently labelled with essentially non-fluorescent lanthanide chelates in combination with time-resolved fluorescence spectroscopy and the reagents to be used in the method
US4822733A (en) * 1985-05-28 1989-04-18 Amoco Corporation Lifetime-resolved assay procedures
US4837169A (en) * 1981-07-01 1989-06-06 Eastman Kodak Company Polypyridine Fluorescent labels for immunoassay
US4855930A (en) * 1987-03-27 1989-08-08 Chimerix Corporation Method and appartatus for improved time-resolved fluorescence spectroscopy
US4859777A (en) * 1981-07-01 1989-08-22 Eastman Kodak Company Terpyridine chelating agents
US4900933A (en) * 1986-09-08 1990-02-13 C. R. Bard, Inc. Excitation and detection apparatus for remote sensor connected by optical fiber
US4920195A (en) * 1985-05-23 1990-04-24 Jouko Kankare Fluorescent lanthanide chelates
US4922113A (en) * 1986-07-10 1990-05-01 Minnesota Mining And Manufacturing Company Process for fluorimetric monitoring of functional coatings and compositions and fluorescent agents therefor
US4923819A (en) * 1987-03-27 1990-05-08 Chimerix Corporation Time-resolved fluorescence immunoassay
US4925804A (en) * 1986-06-17 1990-05-15 Baxter International Inc. Interligand metal transfer assay
US4927923A (en) * 1984-09-26 1990-05-22 Compagnie Oris Industries Macropolycyclic rare earth complexes and application as fluorescent tracers
US4954714A (en) * 1988-09-26 1990-09-04 Hsc Research Development Corporation Apparatus for time-resolved photography of fluorescence
US4965211A (en) * 1979-09-10 1990-10-23 Irwin Wieder Fluorometric analysis method
US4978625A (en) * 1987-10-19 1990-12-18 Becton, Dickinson And Company Fluorescence immunoassay using water insoluble dyes
US4978731A (en) * 1986-07-10 1990-12-18 Minnesota Mining And Manufacturing Company Process for fluorimetric monitoring of functional coatings and compositions and fluorescent agents therefor
US5032677A (en) * 1987-11-06 1991-07-16 Baxter International Inc. Fluorescent poly(arylpyridine) rare earth chelates
US5047444A (en) * 1989-05-31 1991-09-10 Minnesota Mining And Manufacturing Company Fluorescent degree of cure monitors
US5061076A (en) * 1989-01-31 1991-10-29 Enzo Diagnostics, Inc. Time-resolved fluorometer
US5087670A (en) * 1986-07-10 1992-02-11 Minnesota Mining And Manufacturing Company Process for fluorimetric monitoring of functional coatings and compositions and fluorescent agents therefor
US5118559A (en) * 1989-05-31 1992-06-02 Minnesota Mining And Manufacturing Company Fluorescent degree of cure monitors
US5162508A (en) * 1987-12-18 1992-11-10 Compagnie Oris Industrie Rare earth cryptates, processes for their preparation, synthesis intermediates and application as fluorescent tracers
DE4119075A1 (en) * 1991-06-10 1992-12-17 Max Planck Gesellschaft New nucleoside tri:phosphoric acid ester derivs. - used for prepn. of polymerase chain reaction probes, amplification of nucleic acid sequences and as chain terminators for sequences
US5182316A (en) * 1989-05-31 1993-01-26 Minnesota Mining And Manufacturing Company Fluorescent degree of cure monitors
US5187106A (en) * 1984-08-30 1993-02-16 Orbit Medical Systems, Inc. Method and apparatus for homogeneous fluorescence measurements
US5220012A (en) * 1984-09-26 1993-06-15 Compagnie Oris Industrie Sa Macropolycyclic rare earth complexes and application as fluorescent tracers
US5221605A (en) * 1984-10-31 1993-06-22 Igen, Inc. Luminescent metal chelate labels and means for detection
US5238808A (en) * 1984-10-31 1993-08-24 Igen, Inc. Luminescent metal chelate labels and means for detection
US5252834A (en) * 1990-11-13 1993-10-12 Union Oil Company Of California Pulsed and gated multi-mode microspectrophotometry device and method
US5262299A (en) * 1989-12-04 1993-11-16 Kronem Systems, Inc. Enzyme-amplified lanthanide chelate luminescence
US5279297A (en) * 1991-09-20 1994-01-18 Trustees Of The University Of Pennsylvania Method and apparatus for oxygen mapping
US5310604A (en) * 1986-07-10 1994-05-10 Minnesota Mining And Manufacturing Company Composite structure for the fluorimetric monitoring of functional coatings
US5310687A (en) * 1984-10-31 1994-05-10 Igen, Inc. Luminescent metal chelate labels and means for detection
US5315122A (en) * 1992-08-25 1994-05-24 Becton, Dickinson And Company Apparatus and method for fluorescent lifetime measurement
US5317162A (en) * 1991-05-23 1994-05-31 Becton, Dickinson And Company Apparatus and method for phase resolved fluorescence lifetimes of independent and varying amplitude pulses
US5316909A (en) * 1991-03-15 1994-05-31 Wallac Oy Method for increasing fluorescence
US5323008A (en) * 1992-03-23 1994-06-21 Diatron Corporation Fluorometer detection system
US5464741A (en) * 1993-10-08 1995-11-07 Henwell, Inc. Palladium (II) octaethylporphine alpha-isothiocyanate as a phosphorescent label for immunoassays
WO1996018205A1 (en) * 1994-12-08 1996-06-13 Molecular Dynamics, Inc. Fluorescence imaging system employing a macro scanning objective
US5830769A (en) * 1985-03-18 1998-11-03 Wieder; Irwin Homogeneous fluorassay methods employing fluorescent background rejection and water-soluble rare earth metal chelates
US5876960A (en) * 1997-08-11 1999-03-02 The United States Of America As Represented By The Secretary Of The Army Bacterial spore detection and quantification methods
WO1999016009A1 (en) * 1997-09-26 1999-04-01 Iomega Corporation Latent illuminance discrimination marker and system for data storage cartridges
US5955601A (en) * 1991-02-14 1999-09-21 E G & G Wallac Lanthanide chelate conjugated oligonucleotides
US6181662B1 (en) 1997-09-26 2001-01-30 Iomega Corporation Latent irradiance discrimination method and marker system for cartridgeless data storage disks
US6201662B1 (en) 1998-09-25 2001-03-13 Iomega Corporation Latent illuminance discrimination marker with reflective layer for data storage cartridges
EP0770969A3 (en) * 1995-10-23 2001-04-25 Pitney Bowes, Inc. System and method of improving the signal to noise ratio of bar code and indicia scannners that utilize fluorescent inks
US6297924B1 (en) 1998-11-13 2001-10-02 Iomega Corporation System and method for cartridge detection and verification using signal comparison
US6323495B1 (en) 1999-09-24 2001-11-27 Umm Electronics, Inc. Method and apparatus for the determination of phase delay in a lifetime fluorometer without the use of lifetime standards
US6329205B1 (en) 1999-08-31 2001-12-11 Molecular Probes, Inc. Detection method using luminescent europium-based protein stains
US6359745B1 (en) 1997-09-26 2002-03-19 Iomega Corporation Latent illuminance discrimination marker system for data storage cartridges
US6379622B1 (en) 2001-04-11 2002-04-30 Motorola, Inc. Sensor incorporating a quantum dot as a reference
US6454710B1 (en) 2001-04-11 2002-09-24 Motorola, Inc. Devices and methods for monitoring an analyte
US20020182658A1 (en) * 2001-04-11 2002-12-05 Motorola, Inc. Sensor device and methods for manufacture
US6694158B2 (en) 2001-04-11 2004-02-17 Motorola, Inc. System using a portable detection device for detection of an analyte through body tissue
US20040170966A1 (en) * 1999-11-29 2004-09-02 Furfine Eric Steven Continuous time-resolved resonance energy-transfer assay for polynucleic acid polymerases
US7060992B1 (en) 2003-03-10 2006-06-13 Tiax Llc System and method for bioaerosol discrimination by time-resolved fluorescence
US7586604B2 (en) 1997-01-31 2009-09-08 Xy, Inc. Optical apparatus
US7629113B2 (en) 1997-12-31 2009-12-08 Xy, Inc Multiple sexed embryo production system for bovine mammals
WO2010037907A1 (en) 2008-10-03 2010-04-08 Wallac Oy Method and apparatus for detecting undesired measurement conditions
US7713687B2 (en) 2000-11-29 2010-05-11 Xy, Inc. System to separate frozen-thawed spermatozoa into x-chromosome bearing and y-chromosome bearing populations
US7723116B2 (en) 2003-05-15 2010-05-25 Xy, Inc. Apparatus, methods and processes for sorting particles and for providing sex-sorted animal sperm
US7758811B2 (en) 2003-03-28 2010-07-20 Inguran, Llc System for analyzing particles using multiple flow cytometry units
US7820425B2 (en) 1999-11-24 2010-10-26 Xy, Llc Method of cryopreserving selected sperm cells
US7833147B2 (en) 2004-07-22 2010-11-16 Inguran, LLC. Process for enriching a population of sperm cells
US7838210B2 (en) 2004-03-29 2010-11-23 Inguran, LLC. Sperm suspensions for sorting into X or Y chromosome-bearing enriched populations
US7855078B2 (en) 2002-08-15 2010-12-21 Xy, Llc High resolution flow cytometer
US20120038907A1 (en) * 2010-08-13 2012-02-16 Leica Microsystems Cms Gmbh Method for separating detection signals in the beam path of an optical device
US8137967B2 (en) 2000-11-29 2012-03-20 Xy, Llc In-vitro fertilization systems with spermatozoa separated into X-chromosome and Y-chromosome bearing populations
US20120127467A1 (en) * 2009-08-04 2012-05-24 Asml Netherland B.V. Object Inspection Systems and Methods
US8211629B2 (en) 2002-08-01 2012-07-03 Xy, Llc Low pressure sperm cell separation system
US8486618B2 (en) 2002-08-01 2013-07-16 Xy, Llc Heterogeneous inseminate system
WO2015168740A1 (en) 2014-05-07 2015-11-12 Nplex Pty Ltd Synthetic thread based lateral flow immunoassay
US9365822B2 (en) 1997-12-31 2016-06-14 Xy, Llc System and method for sorting cells
US20160274079A1 (en) * 2013-11-19 2016-09-22 Aqsens Oy Method of analysis
US11230695B2 (en) 2002-09-13 2022-01-25 Xy, Llc Sperm cell processing and preservation systems

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1111762A (en) * 1977-12-28 1981-11-03 David S. Frank Fluorescent rare earth chelate in polymeric latex particles
US4256834A (en) * 1979-04-09 1981-03-17 Syva Company Fluorescent scavenger particle immunoassay
DE3025022C2 (en) 1980-07-02 1985-07-04 Wang, Wei-Kung, T'ai-pei Method for the determination of biological particles by induced signals
CA1205028A (en) * 1981-07-01 1986-05-27 Jerald C. Hinshaw Fluorescent chelates and labeled specific binding reagents prepared therefrom
CA1174076A (en) * 1981-12-02 1984-09-11 Eastman Kodak Company Normalized radiometer and method of measuring analytes
SE454115B (en) * 1982-09-13 1988-03-28 Wallac Oy HOMOGENIC PHASE ANALYSIS WITH LANTANIDE KELAT AS BRAND SUBSTANCE
US4680275A (en) * 1985-02-11 1987-07-14 Becton, Dickinson And Company Homogeneous fluorescence immunoassay using a light absorbing material
DD254998A1 (en) * 1985-07-26 1988-03-16 Zeiss Jena Veb Carl ARRANGEMENT FOR THE IMAGE AND ANALYSIS OF FLUORESCENCE SIGNALS
GB8601646D0 (en) * 1986-01-23 1986-02-26 Davidson R S Binding assay & reagent
DE3915692A1 (en) * 1989-05-13 1990-11-22 Strahlen Umweltforsch Gmbh Fluorescence process measuring method - using switched laser, fluorescent light detection system with variable gain
DE69118429T2 (en) * 1990-01-26 1996-09-12 Canon Kk Method of measuring a species using fluorescent light
DE4416558C2 (en) * 1994-02-01 1997-09-04 Hell Stefan Method for optically measuring a sample point of a sample and device for carrying out the method
DE4420572C2 (en) * 1994-06-03 1999-02-04 Hartmut Dr Rer Nat Lucht Device for determining the concentration of fluorescent substances

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3842264A (en) * 1970-12-30 1974-10-15 Texaco Inc Radiological well logging methods and apparatus for reducing the effect of activation from the detector crystal
US3886363A (en) * 1973-01-20 1975-05-27 Hitachi Ltd Spectro fluorescence and absorption measuring instrument
US4006360A (en) * 1974-08-21 1977-02-01 Block Engineering, Inc. Method of discriminating between dyed particles and background fluorescence of the dye

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2975966A (en) * 1956-04-09 1961-03-21 Burroughs Corp Coded document reader
US3412245A (en) * 1966-02-09 1968-11-19 American Cyanamid Co Method and apparatus of retrieval of coded information from symbols having coded inks having photoluminescent components with short and long time constants of decay after short wave illumination
US3918812A (en) * 1973-05-07 1975-11-11 Us Energy Diagnoses of disease states by fluorescent measurements utilizing scanning laser beams

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3842264A (en) * 1970-12-30 1974-10-15 Texaco Inc Radiological well logging methods and apparatus for reducing the effect of activation from the detector crystal
US3886363A (en) * 1973-01-20 1975-05-27 Hitachi Ltd Spectro fluorescence and absorption measuring instrument
US4006360A (en) * 1974-08-21 1977-02-01 Block Engineering, Inc. Method of discriminating between dyed particles and background fluorescence of the dye

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
"Gated Nanosecond Time Resolved Emission Spectroscopy Separation of Mixed Emissions from Carbonyl Compounds", R. E. Brown et al., Analytical Chemistry, vol. 46, p. 1690 (1974). *

Cited By (136)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4341957A (en) * 1975-11-26 1982-07-27 Analytical Radiation Corporation Fluorescent antibody composition for immunofluorometric assay
US4284897A (en) * 1977-04-30 1981-08-18 Olympus Optical Company Ltd. Fluorescence determining microscope utilizing laser light
US4171956A (en) * 1977-06-13 1979-10-23 General Electric Company Laser immunoassay
US4198567A (en) * 1977-10-25 1980-04-15 Peter Eneroth Method and apparatus for discrimination between scattered excitation radiation and low level fast decaying fluorescent radiation
US4150295A (en) * 1978-01-05 1979-04-17 Analytical Radiation Corporation Method and apparatus for background correction in photoluminescent analysis
US4222744A (en) * 1978-09-27 1980-09-16 Becton Dickinson & Company Assay for ligands
US4390274A (en) * 1979-01-18 1983-06-28 Fritz Berthold Use of a method, particularly an automatic method, for measuring light as well as improvements and apparatuses for carrying out the same
US4238195A (en) * 1979-01-18 1980-12-09 Miles Laboratories, Inc. Fluorescer-labeled specific binding assays
US4374120A (en) * 1979-03-08 1983-02-15 Wallac Oy Fluorescence spectroscopy assay means with fluorescent chelate of a lanthanide
US4965211A (en) * 1979-09-10 1990-10-23 Irwin Wieder Fluorometric analysis method
US4432907A (en) * 1979-09-10 1984-02-21 Analytical Radiation Corporation Diamine acid fluorescent chelates
US4259574A (en) * 1979-11-06 1981-03-31 International Business Machines Corporation Microanalysis by pulse laser emission spectroscopy
US4373932A (en) * 1980-01-11 1983-02-15 Akzona Incorporated Application of water-dispersible hydrophobic dyes or pigments as labels in immunoassays
EP0064484A2 (en) * 1981-04-30 1982-11-10 Wallac Oy Method for fluorescence spectroscopic determination of a biologically active substance
EP0064484A3 (en) * 1981-04-30 1983-01-19 Wallac Oy Method for fluorescence spectroscopic determination of a biologically active substance
US4637988A (en) * 1981-07-01 1987-01-20 Eastman Kodak Company Fluorescent labels for immunoassay
US4859777A (en) * 1981-07-01 1989-08-22 Eastman Kodak Company Terpyridine chelating agents
US4837169A (en) * 1981-07-01 1989-06-06 Eastman Kodak Company Polypyridine Fluorescent labels for immunoassay
US4794191A (en) * 1981-07-01 1988-12-27 Eastman Kodak Company Fluorescent chelates
US4801722A (en) * 1981-07-01 1989-01-31 Eastman Kodak Company Coumarin chelates
US4808541A (en) * 1983-03-15 1989-02-28 Lkb Produkter Ab Determination method utilizing reagents covalently labelled with essentially non-fluorescent lanthanide chelates in combination with time-resolved fluorescence spectroscopy and the reagents to be used in the method
US4778593A (en) * 1983-03-25 1988-10-18 Agency Of Industrial Science And Technology Method and apparatus for discriminating minute particles
US4614723A (en) * 1983-06-03 1986-09-30 Hoffmann-La Roche Inc. Porphyrin derivatives as fluorescent markers for immunoassays
US5187106A (en) * 1984-08-30 1993-02-16 Orbit Medical Systems, Inc. Method and apparatus for homogeneous fluorescence measurements
US5220012A (en) * 1984-09-26 1993-06-15 Compagnie Oris Industrie Sa Macropolycyclic rare earth complexes and application as fluorescent tracers
US5432101A (en) * 1984-09-26 1995-07-11 Compagnie Oris Industrie Sa Macropolycyclic rare earth complexes and application as fluorescent tracers
US4927923A (en) * 1984-09-26 1990-05-22 Compagnie Oris Industries Macropolycyclic rare earth complexes and application as fluorescent tracers
US5238808A (en) * 1984-10-31 1993-08-24 Igen, Inc. Luminescent metal chelate labels and means for detection
US5221605A (en) * 1984-10-31 1993-06-22 Igen, Inc. Luminescent metal chelate labels and means for detection
US5453356A (en) * 1984-10-31 1995-09-26 Igen, Inc. Luminescent metal chelate labels and means for detection
US6140138A (en) * 1984-10-31 2000-10-31 Igen International Inc. Electrochemiluminescent metal chelates and means for detection
US5714089A (en) * 1984-10-31 1998-02-03 Igen International, Inc. Luminescent metal chelatte labels and means for detection
US5310687A (en) * 1984-10-31 1994-05-10 Igen, Inc. Luminescent metal chelate labels and means for detection
US5731147A (en) * 1984-10-31 1998-03-24 Igen International, Inc. Luminescent metal chelate labels and means for detection
US6242268B1 (en) 1985-03-18 2001-06-05 Eg&G Wallac Homogeneous fluorassay methods employing fluorescent background rejection and water-soluble rare earth metal chelates
US5830769A (en) * 1985-03-18 1998-11-03 Wieder; Irwin Homogeneous fluorassay methods employing fluorescent background rejection and water-soluble rare earth metal chelates
US4920195A (en) * 1985-05-23 1990-04-24 Jouko Kankare Fluorescent lanthanide chelates
US4822733A (en) * 1985-05-28 1989-04-18 Amoco Corporation Lifetime-resolved assay procedures
WO1987004716A1 (en) * 1986-01-30 1987-08-13 Salifu Dakubu Use of lanthanide chelate fluorophores based on dihydropyridine condensation products
US4968631A (en) * 1986-01-30 1990-11-06 Golight, Inc. Method for detecting amines and aldehydes using lanthanide chelate fluorophores based on dihydropyridine condensation products
EP0242527A3 (en) * 1986-02-19 1989-06-14 Enzo Biochem, Inc. Analyte detection by means of energy transfer
EP0242527A2 (en) * 1986-02-19 1987-10-28 Enzo Biochem, Inc. Analyte detection by means of energy transfer
US4925804A (en) * 1986-06-17 1990-05-15 Baxter International Inc. Interligand metal transfer assay
WO1987007955A1 (en) * 1986-06-17 1987-12-30 Baxter Travenol Laboratories, Inc. Homogeneous fluoroassay methods employing fluorescent background rejection and water-soluble rare earth metal chelate fluorophores
US5310604A (en) * 1986-07-10 1994-05-10 Minnesota Mining And Manufacturing Company Composite structure for the fluorimetric monitoring of functional coatings
US4922113A (en) * 1986-07-10 1990-05-01 Minnesota Mining And Manufacturing Company Process for fluorimetric monitoring of functional coatings and compositions and fluorescent agents therefor
US5087670A (en) * 1986-07-10 1992-02-11 Minnesota Mining And Manufacturing Company Process for fluorimetric monitoring of functional coatings and compositions and fluorescent agents therefor
US4978731A (en) * 1986-07-10 1990-12-18 Minnesota Mining And Manufacturing Company Process for fluorimetric monitoring of functional coatings and compositions and fluorescent agents therefor
US4900933A (en) * 1986-09-08 1990-02-13 C. R. Bard, Inc. Excitation and detection apparatus for remote sensor connected by optical fiber
US4791310A (en) * 1986-10-02 1988-12-13 Syracuse University Fluorescence microscopy
US4923819A (en) * 1987-03-27 1990-05-08 Chimerix Corporation Time-resolved fluorescence immunoassay
US4855930A (en) * 1987-03-27 1989-08-08 Chimerix Corporation Method and appartatus for improved time-resolved fluorescence spectroscopy
US4978625A (en) * 1987-10-19 1990-12-18 Becton, Dickinson And Company Fluorescence immunoassay using water insoluble dyes
US5032677A (en) * 1987-11-06 1991-07-16 Baxter International Inc. Fluorescent poly(arylpyridine) rare earth chelates
US5534622A (en) * 1987-12-18 1996-07-09 Compagnie Oris Industrie, Sa Rare earth cryptates, processes for their preparation, synthesis intermediates and application as fluorescent tracers
US5457185A (en) * 1987-12-18 1995-10-10 Societe Anonyme: Compagnie Oris Industrie Rare earth cryptates, processes for their preparation, synthesis intermediates and application as fluorescent tracers
US5162508A (en) * 1987-12-18 1992-11-10 Compagnie Oris Industrie Rare earth cryptates, processes for their preparation, synthesis intermediates and application as fluorescent tracers
US5346996A (en) * 1987-12-18 1994-09-13 Compagnie Oris Industrie Rare earth cryptates, processes for their preparation, synthesis intermediates and application as fluorescent tracers
US4954714A (en) * 1988-09-26 1990-09-04 Hsc Research Development Corporation Apparatus for time-resolved photography of fluorescence
US5061076A (en) * 1989-01-31 1991-10-29 Enzo Diagnostics, Inc. Time-resolved fluorometer
US5047444A (en) * 1989-05-31 1991-09-10 Minnesota Mining And Manufacturing Company Fluorescent degree of cure monitors
US5182316A (en) * 1989-05-31 1993-01-26 Minnesota Mining And Manufacturing Company Fluorescent degree of cure monitors
US5118559A (en) * 1989-05-31 1992-06-02 Minnesota Mining And Manufacturing Company Fluorescent degree of cure monitors
US5262299A (en) * 1989-12-04 1993-11-16 Kronem Systems, Inc. Enzyme-amplified lanthanide chelate luminescence
US5252834A (en) * 1990-11-13 1993-10-12 Union Oil Company Of California Pulsed and gated multi-mode microspectrophotometry device and method
US5955601A (en) * 1991-02-14 1999-09-21 E G & G Wallac Lanthanide chelate conjugated oligonucleotides
US5316909A (en) * 1991-03-15 1994-05-31 Wallac Oy Method for increasing fluorescence
US5317162A (en) * 1991-05-23 1994-05-31 Becton, Dickinson And Company Apparatus and method for phase resolved fluorescence lifetimes of independent and varying amplitude pulses
DE4119075A1 (en) * 1991-06-10 1992-12-17 Max Planck Gesellschaft New nucleoside tri:phosphoric acid ester derivs. - used for prepn. of polymerase chain reaction probes, amplification of nucleic acid sequences and as chain terminators for sequences
US5279297A (en) * 1991-09-20 1994-01-18 Trustees Of The University Of Pennsylvania Method and apparatus for oxygen mapping
US5323008A (en) * 1992-03-23 1994-06-21 Diatron Corporation Fluorometer detection system
US5315122A (en) * 1992-08-25 1994-05-24 Becton, Dickinson And Company Apparatus and method for fluorescent lifetime measurement
US5464741A (en) * 1993-10-08 1995-11-07 Henwell, Inc. Palladium (II) octaethylporphine alpha-isothiocyanate as a phosphorescent label for immunoassays
US5719391A (en) * 1994-12-08 1998-02-17 Molecular Dynamics, Inc. Fluorescence imaging system employing a macro scanning objective
WO1996018205A1 (en) * 1994-12-08 1996-06-13 Molecular Dynamics, Inc. Fluorescence imaging system employing a macro scanning objective
EP0770969A3 (en) * 1995-10-23 2001-04-25 Pitney Bowes, Inc. System and method of improving the signal to noise ratio of bar code and indicia scannners that utilize fluorescent inks
US7586604B2 (en) 1997-01-31 2009-09-08 Xy, Inc. Optical apparatus
US7929137B2 (en) 1997-01-31 2011-04-19 Xy, Llc Optical apparatus
US5876960A (en) * 1997-08-11 1999-03-02 The United States Of America As Represented By The Secretary Of The Army Bacterial spore detection and quantification methods
US6181662B1 (en) 1997-09-26 2001-01-30 Iomega Corporation Latent irradiance discrimination method and marker system for cartridgeless data storage disks
US6091563A (en) * 1997-09-26 2000-07-18 Iomega Corporation Latent illuminance discrimination marker system for data storage cartridges
US6359745B1 (en) 1997-09-26 2002-03-19 Iomega Corporation Latent illuminance discrimination marker system for data storage cartridges
WO1999016009A1 (en) * 1997-09-26 1999-04-01 Iomega Corporation Latent illuminance discrimination marker and system for data storage cartridges
US9365822B2 (en) 1997-12-31 2016-06-14 Xy, Llc System and method for sorting cells
US9422523B2 (en) 1997-12-31 2016-08-23 Xy, Llc System and method for sorting cells
US7629113B2 (en) 1997-12-31 2009-12-08 Xy, Inc Multiple sexed embryo production system for bovine mammals
US6201662B1 (en) 1998-09-25 2001-03-13 Iomega Corporation Latent illuminance discrimination marker with reflective layer for data storage cartridges
US6297924B1 (en) 1998-11-13 2001-10-02 Iomega Corporation System and method for cartridge detection and verification using signal comparison
US6329205B1 (en) 1999-08-31 2001-12-11 Molecular Probes, Inc. Detection method using luminescent europium-based protein stains
US6323495B1 (en) 1999-09-24 2001-11-27 Umm Electronics, Inc. Method and apparatus for the determination of phase delay in a lifetime fluorometer without the use of lifetime standards
US7820425B2 (en) 1999-11-24 2010-10-26 Xy, Llc Method of cryopreserving selected sperm cells
US20040170966A1 (en) * 1999-11-29 2004-09-02 Furfine Eric Steven Continuous time-resolved resonance energy-transfer assay for polynucleic acid polymerases
US7713687B2 (en) 2000-11-29 2010-05-11 Xy, Inc. System to separate frozen-thawed spermatozoa into x-chromosome bearing and y-chromosome bearing populations
US9879221B2 (en) 2000-11-29 2018-01-30 Xy, Llc Method of in-vitro fertilization with spermatozoa separated into X-chromosome and Y-chromosome bearing populations
US8652769B2 (en) 2000-11-29 2014-02-18 Xy, Llc Methods for separating frozen-thawed spermatozoa into X-chromosome bearing and Y-chromosome bearing populations
US7771921B2 (en) 2000-11-29 2010-08-10 Xy, Llc Separation systems of frozen-thawed spermatozoa into X-chromosome bearing and Y-chromosome bearing populations
US8137967B2 (en) 2000-11-29 2012-03-20 Xy, Llc In-vitro fertilization systems with spermatozoa separated into X-chromosome and Y-chromosome bearing populations
US7521019B2 (en) 2001-04-11 2009-04-21 Lifescan, Inc. Sensor device and methods for manufacture
US6694158B2 (en) 2001-04-11 2004-02-17 Motorola, Inc. System using a portable detection device for detection of an analyte through body tissue
US20020182658A1 (en) * 2001-04-11 2002-12-05 Motorola, Inc. Sensor device and methods for manufacture
US6454710B1 (en) 2001-04-11 2002-09-24 Motorola, Inc. Devices and methods for monitoring an analyte
US6379622B1 (en) 2001-04-11 2002-04-30 Motorola, Inc. Sensor incorporating a quantum dot as a reference
US8497063B2 (en) 2002-08-01 2013-07-30 Xy, Llc Sex selected equine embryo production system
US8486618B2 (en) 2002-08-01 2013-07-16 Xy, Llc Heterogeneous inseminate system
US8211629B2 (en) 2002-08-01 2012-07-03 Xy, Llc Low pressure sperm cell separation system
US7855078B2 (en) 2002-08-15 2010-12-21 Xy, Llc High resolution flow cytometer
US11261424B2 (en) 2002-09-13 2022-03-01 Xy, Llc Sperm cell processing systems
US11230695B2 (en) 2002-09-13 2022-01-25 Xy, Llc Sperm cell processing and preservation systems
US7060992B1 (en) 2003-03-10 2006-06-13 Tiax Llc System and method for bioaerosol discrimination by time-resolved fluorescence
US8748183B2 (en) 2003-03-28 2014-06-10 Inguran, Llc Method and apparatus for calibrating a flow cytometer
US8664006B2 (en) 2003-03-28 2014-03-04 Inguran, Llc Flow cytometer apparatus and method
US9377390B2 (en) 2003-03-28 2016-06-28 Inguran, Llc Apparatus, methods and processes for sorting particles and for providing sex-sorted animal sperm
US10100278B2 (en) 2003-03-28 2018-10-16 Inguran, Llc Multi-channel system and methods for sorting particles
US11718826B2 (en) 2003-03-28 2023-08-08 Inguran, Llc System and method for sorting particles
US7799569B2 (en) 2003-03-28 2010-09-21 Inguran, Llc Process for evaluating staining conditions of cells for sorting
US7758811B2 (en) 2003-03-28 2010-07-20 Inguran, Llc System for analyzing particles using multiple flow cytometry units
US11104880B2 (en) 2003-03-28 2021-08-31 Inguran, Llc Photo-damage system for sorting particles
US8709817B2 (en) 2003-03-28 2014-04-29 Inguran, Llc Systems and methods for sorting particles
US8709825B2 (en) 2003-03-28 2014-04-29 Inguran, Llc Flow cytometer method and apparatus
US7943384B2 (en) 2003-03-28 2011-05-17 Inguran Llc Apparatus and methods for sorting particles
US9040304B2 (en) 2003-03-28 2015-05-26 Inguran, Llc Multi-channel system and methods for sorting particles
US7723116B2 (en) 2003-05-15 2010-05-25 Xy, Inc. Apparatus, methods and processes for sorting particles and for providing sex-sorted animal sperm
US7892725B2 (en) 2004-03-29 2011-02-22 Inguran, Llc Process for storing a sperm dispersion
US7838210B2 (en) 2004-03-29 2010-11-23 Inguran, LLC. Sperm suspensions for sorting into X or Y chromosome-bearing enriched populations
US7833147B2 (en) 2004-07-22 2010-11-16 Inguran, LLC. Process for enriching a population of sperm cells
AU2009299715B2 (en) * 2008-10-03 2012-05-31 Wallac Oy Method and apparatus for detecting undesired measurement conditions
WO2010037907A1 (en) 2008-10-03 2010-04-08 Wallac Oy Method and apparatus for detecting undesired measurement conditions
US20110033872A1 (en) * 2008-10-03 2011-02-10 Wallac Oy Method and apparatus for detecting undesired measurement conditions
US9122178B2 (en) * 2009-08-04 2015-09-01 Asml Netherlands B.V. Object inspection systems and methods
US20120127467A1 (en) * 2009-08-04 2012-05-24 Asml Netherland B.V. Object Inspection Systems and Methods
US9651765B2 (en) * 2010-08-13 2017-05-16 Leica Microsystems Cms Gmbh Method for separating detection signals in the beam path of an optical device
US20120038907A1 (en) * 2010-08-13 2012-02-16 Leica Microsystems Cms Gmbh Method for separating detection signals in the beam path of an optical device
US20160274079A1 (en) * 2013-11-19 2016-09-22 Aqsens Oy Method of analysis
US10156558B2 (en) * 2013-11-19 2018-12-18 Kemira Oyj Detection and quantification of polymeric analytes using fluorescent lanthanide detection not relying on charge transfer from polymer aromatic groups
WO2015168740A1 (en) 2014-05-07 2015-11-12 Nplex Pty Ltd Synthetic thread based lateral flow immunoassay
US10379119B2 (en) 2014-05-07 2019-08-13 Lumos Diagnostics IP Pty Ltd Synthetic thread based lateral flow immunoassay

Also Published As

Publication number Publication date
GB1560402A (en) 1980-02-06
DE2660391C2 (en) 1986-08-07
IT1062498B (en) 1984-10-10
DE2628158B2 (en) 1979-11-15
DE2628158C3 (en) 1980-08-07
FR2316595A1 (en) 1977-01-28
JPS5210796A (en) 1977-01-27
CA1082106A (en) 1980-07-22
FR2316595B1 (en) 1982-02-19
DE2628158A1 (en) 1977-02-03
GB1560403A (en) 1980-02-06

Similar Documents

Publication Publication Date Title
US4058732A (en) Method and apparatus for improved analytical fluorescent spectroscopy
US4006360A (en) Method of discriminating between dyed particles and background fluorescence of the dye
CA1319743C (en) Area-modulated luminescence (aml)
Mauzerall Light-induced fluorescence changes in Chlorella, and the primary photoreactions for the production of oxygen
JP3215428B2 (en) Biospecific multi-parameter assays
US6444476B1 (en) Luminescence assay using cyclical excitation wavelength sequence
Keller et al. Single-molecule fluorescence analysis in solution
US4100416A (en) Serum fluorescence suppression
US4341957A (en) Fluorescent antibody composition for immunofluorometric assay
US4146604A (en) Differential counting of leukocytes and other cells
Kirkbright et al. The detection and determination of polynuclear aromatic hydrocarbons by luminescence spectrometry utilising the Shpol'skii effect at 77 K
US6140048A (en) System for distinguishing fluorescent molecule groups by time resolved fluorescence measurement
US5190857A (en) Optical method for measuring an analyte using area-modulated luminescence
US4018530A (en) Fluorescence spectrometry employing excitation of bleaching intensity
McClain et al. On the nature of stimulated emission in rigid organic solutions
US20130171623A1 (en) Binding Assays Utilizing Time-Resolved Up-Converting Luminescence Detection
WO1988007670A2 (en) Time-resolved fluorescence apparatus and immunoassay
Morgan et al. Fluorescence lifetime imaging: an emerging technique in fluorescence microscopy
Miller Photoluminescence and chemiluminescence methods of drug analysis
Collette et al. The role of Raman spectroscopy in the analytical chemistry of potable water
Futoma et al. Spectroscopic methods of analysis for polycyclic aromatic hydrocarbons in the aqueous environment
Parola et al. Laser photobleaching of human serum: Application to fluorescence immunoassays
Axner et al. Analytical applications of laser-enhanced lonization spectrometry in flames and furnaces
GB1566423A (en) Photometric system
RU2049986C1 (en) Method of detection of ions of metals in solutions

Legal Events

Date Code Title Description
STCF Information on status: patent grant

Free format text: PATENTED FILE - (OLD CASE ADDED FOR FILE TRACKING PURPOSES)

AS Assignment

Owner name: WIEDER, IRWIN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ANALYTICAL RADIATION CORPORATION;REEL/FRAME:004288/0226

Effective date: 19810707

Owner name: WIEDER, IRWIN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ANALYTICAL RADIATION CORPORATION;REEL/FRAME:004288/0226

Effective date: 19810707